This seems to offer a way to make WordPress create .webp thumbnails when uploading a .jpeg file (and the other way around!).

I know support for .webp has been added with WordPress 5.8, but there was no core support for creating fallback .jpeg thumbnails when uploading a .webp image, nor would .webp thumbnails be generated when uploading a .jpeg.

A full-size image in the opposite format is not being generated, though.

Will this behaviour be added to core in the future? Alternatively, will hooks be provided to enable the behaviour? Or are they already available? Or do we simply need to install this Performance Lab plugin for this?

Of course I would very much like this to be available in core without any extra plugins. Using a hook to enable generating .webp images from a .jpeg and vice versa would be a solution as well.